Jonhnathan
a3d7427d29
* Add Investigation Guides for Windows Rules - First half * + 1/2 * Update impact_volume_shadow_copy_deletion_or_resized_via_vssadmin.toml * Update credential_access_mod_wdigest_security_provider.toml * Apply suggestions from code review Co-authored-by: Mika Ayenson <Mikaayenson@users.noreply.github.com> * Update defense_evasion_amsienable_key_mod.toml * Update defense_evasion_amsienable_key_mod.toml * Apply suggestions from code review Co-authored-by: benironside <91905639+benironside@users.noreply.github.com> * Update command_and_control_certutil_network_connection.toml * Apply suggestions from code review Co-authored-by: nastasha-solomon <79124755+nastasha-solomon@users.noreply.github.com> Co-authored-by: Joe Peeples <joe.peeples@elastic.co> Co-authored-by: benironside <91905639+benironside@users.noreply.github.com> * Update collection_winrar_encryption.toml * Apply suggestions from code review Co-authored-by: nastasha-solomon <79124755+nastasha-solomon@users.noreply.github.com> Co-authored-by: Colson Wilhoit <48036388+DefSecSentinel@users.noreply.github.com> Co-authored-by: Mika Ayenson <Mikaayenson@users.noreply.github.com> Co-authored-by: benironside <91905639+benironside@users.noreply.github.com> Co-authored-by: nastasha-solomon <79124755+nastasha-solomon@users.noreply.github.com> Co-authored-by: Joe Peeples <joe.peeples@elastic.co>
89 lines
3.8 KiB
TOML
89 lines
3.8 KiB
TOML
[metadata]
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creation_date = "2020/03/19"
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maturity = "production"
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updated_date = "2022/03/07"
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[rule]
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author = ["Elastic"]
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description = """
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Identifies certutil.exe making a network connection. Adversaries could abuse certutil.exe to download a certificate, or
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malware, from a remote URL.
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"""
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from = "now-9m"
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index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*"]
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language = "eql"
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license = "Elastic License v2"
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name = "Network Connection via Certutil"
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note = """## Triage and analysis
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### Investigating Network Connection via Certutil
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Attackers can abuse `certutil.exe` to download malware, offensive security tools, and certificates from external sources
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in order to take the next steps in a compromised environment.
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This rule looks for network events where `certutil.exe` contacts IP ranges other than the ones specified in
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[IANA IPv4 Special-Purpose Address Registry](https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml)
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#### Possible investigation steps
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- Investigate the script execution chain (parent process tree).
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- Investigate other alerts related to the user/host in the last 48 hours.
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- Investigate if the downloaded file was executed.
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- Determine the context in which `certutil.exe` and the file were run.
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- Retrieve the file downloaded and:
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- Use a sandboxed malware analysis system to perform analysis.
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- Observe attempts of contacting external domains and addresses.
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- Use the PowerShell Get-FileHash cmdlet to get the SHA-256 hash value of the file.
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- Search for the existence of this file in resources like VirusTotal, Hybrid-Analysis, CISCO Talos, Any.run, etc.
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### False positive analysis
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- This mechanism can be used legitimately. If trusted software uses this command and the triage has not identified
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anything suspicious, this alert can be closed as a false positive.
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- If this activity is expected and noisy in your environment, consider adding exceptions — preferably with a combination
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of user and command line conditions.
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### Response and remediation
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- Initiate the incident response process based on the outcome of the triage.
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- Isolate the involved host to prevent further post-compromise behavior.
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- If the triage identified malware, search the environment for additional compromised hosts.
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- Implement any temporary network rules, procedures, and segmentation required to contain the malware.
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"""
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references = [
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"https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml",
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"https://frsecure.com/malware-incident-response-playbook/",
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]
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risk_score = 21
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rule_id = "3838e0e3-1850-4850-a411-2e8c5ba40ba8"
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severity = "low"
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tags = ["Elastic", "Host", "Windows", "Threat Detection", "Command and Control"]
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type = "eql"
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query = '''
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sequence by process.entity_id
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[process where process.name : "certutil.exe" and event.type == "start"]
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[network where process.name : "certutil.exe" and
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not cidrmatch(destination.ip, "10.0.0.0/8", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12", "192.0.0.0/24",
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"192.0.0.0/29", "192.0.0.8/32", "192.0.0.9/32", "192.0.0.10/32", "192.0.0.170/32",
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"192.0.0.171/32", "192.0.2.0/24", "192.31.196.0/24", "192.52.193.0/24",
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"192.168.0.0/16", "192.88.99.0/24", "224.0.0.0/4", "100.64.0.0/10", "192.175.48.0/24",
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"198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24", "240.0.0.0/4", "::1",
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"FE80::/10", "FF00::/8")]
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'''
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[[rule.threat]]
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framework = "MITRE ATT&CK"
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[[rule.threat.technique]]
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id = "T1105"
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name = "Ingress Tool Transfer"
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reference = "https://attack.mitre.org/techniques/T1105/"
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[rule.threat.tactic]
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id = "TA0011"
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name = "Command and Control"
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reference = "https://attack.mitre.org/tactics/TA0011/"
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